Towards real-world TRWP quantification: Combining a novel enclosed collection system with optical sensors to mitigate particle loss in tire emission measurements

The significant impacts of tire and road wear particles (TRWP) on human health and the environment are increasingly being recognized. As a major source of microplastics, tire abrasion presents a pressing challenge, especially with the introduction of the Euro 7 standard, which will regulate brake and tire wear emissions for the first time. However, the absence of standardized methods for airborne TRWP measurements remains a critical barrier. Accurate quantification of airborne TRWP emissions requires complex measurement systems, which are often susceptible to particle loss during sampling.As part of the “Models and Data for Future Mobility_Supporting Services (MoDa)” project, we aim to develop customer-oriented solutions to support the transformation of the transport sector. One such solution is AirQualityLive (AQL), designed to generate actionable insights from air quality data and enable evidence-based decision-making for cleaner and more sustainable mobility.This study aimed to enhance measurement precision and mitigate particle loss during tire emission assessments conducted on a chassis dynamometer test bench during Worldwide Harmonized Light Vehicles Test Cycles (WLTCs) applied to a electric car. To achieve this, we designed an enclosed tire system (patent pending) and tested the integration of low-cost optical particle counters (OPCs) to measure airborne tire emissions. Two isokinetic particle collection systems were compared: (1) a closed collection system encapsulating the tire, isolating it from brake and environmental interferences, and (2) an open collection system. For that purpose, two parallel set-ups were mounted behind the back tires including for each system gravimetric measurements of PM10 and PM2.5, a cascade impactor with four particle size stages (>PM10, PM2.5–10, PM2.5, and